Anna was one of the ones I was reading about as it happens.Tbh, Russia's/USSR's history is littered with assainations of dissidents, and people who oppose the regime. You can look back all the way to the Tsars in the 18th century for recorded history of these happening all the time. Irocically, I've just finished watching Litvinenko on itv. Can't believe that was 2006 - seems such a long time ago, and in the same year, a month before, Anna Politkovskaya, a Russian anti-Putin journalist was assasinated who had close ties to Litvinenko. All of these had direct links back to Putin.
There is a list posted that I came across of Journalists etc that have been killed or dissapeared under Putin. It's not a small list!